Cool Roofs in Phoenix: How Reflective Roofing Works and When It Pays

2026-10-04 · 8 min read

A dark roof in a Phoenix summer can run well over 150 degrees. A cool roof reflects more of the sun and sheds heat faster, so it runs much cooler. Here's how the ratings work, which cool options exist for each type of Valley roof, what rebates are actually available, and where a cool roof makes the biggest difference.

What makes a roof cool

A cool roof is one that stays cooler in the sun than a conventional roof. Two measurable properties decide that:

Solar reflectance: the share of sunlight the surface reflects instead of absorbing, on a scale from 0 to 1. A bright white coating can reflect most of the sun; a dark shingle reflects very little.
Thermal emittance: how well the surface releases the heat it does absorb, also from 0 to 1. Most non-metal roofing emits well; bare, shiny metal doesn't, which is why metal roofs use coated finishes.

The Solar Reflectance Index (SRI) combines the two into one number, where a higher value means a cooler roof.

The practical result, according to the U.S. Department of Energy, is that a standard or dark roof can exceed 150 degrees in summer sun, while a cool roof under the same conditions can stay more than 50 degrees cooler. In Phoenix, where roof surfaces regularly hit 150 to 170 degrees and the city now sees around three weeks of 110-degree days in a typical year, that difference is felt in the attic and on the cooling bill.

Cool doesn't have to mean white

White reflects the most, but it isn't the only option, and many HOAs won't allow a white pitched roof anyway.

About half of the sun's energy arrives as near-infrared light, which you can't see. Cool-colored products use pigments that reflect a lot of that invisible infrared while still looking tan, terracotta, gray or brown. A cool-colored product will never match white, but it can reflect noticeably more than a standard product of the same visible color.

That's what cool-rated shingles, cool-finish metal and many light tile colors rely on. IKO's Cambridge Cool Colors line, for example, uses reflective granules to raise reflectance in shingle colors that look like ordinary architectural shingles.

How to read cool roof ratings

Marketing names like "cool" or "reflective" don't tell you much. Ratings do.

The Cool Roof Rating Council (CRRC) runs the main independent rating program in the U.S. Its product directory lists tested values for solar reflectance and thermal emittance, both initial and after three years of weathering outdoors.

Pay attention to the aged numbers. Dust, pollution and biological growth lower reflectance over time, and Phoenix has plenty of dust. A product's three-year aged reflectance is a better guide to how it will actually perform on a Valley roof than its brand-new rating.

One label you won't find anymore: the ENERGY STAR program for roof products ended on June 1, 2022, so roofing products no longer carry that mark. Anyone quoting an ENERGY STAR-certified roof is working from old information.

Cool options for flat and low-slope roofs

Flat and low-slope roofs gain the most from going cool, because they face the sun all day and can take bright white surfaces without anyone seeing them from the street.

Foam (SPF) with a reflective coating. A white elastomeric coating over spray foam combines a reflective surface with insulation built into the roof (roofing-grade foam is rated around R-6.5 per inch by its manufacturers). A new foam roof runs about $5.00 to $8.00 per square foot.
Foam recoat. If the foam underneath is sound, cleaning, minor repairs and a new reflective coating restore the cool surface for about $2.00 to $3.75 per square foot. On a dusty Valley roof, a recoat also renews reflectance that has dulled over the years.
TPO membrane. White single-ply TPO is reflective out of the box, with heat-welded seams. It runs about $5.50 to $9.00 per square foot.

For commercial buildings, the International Energy Conservation Code requires low-slope roofs in climate zones 0 through 3, which include the Phoenix area, to meet a three-year aged solar reflectance of at least 0.55 with thermal emittance of at least 0.75, or an aged SRI of at least 64, subject to exceptions. Arizona has no statewide building code, so whether that applies depends on the edition your city adopted and the project.

Cool options for pitched roofs

On tile and shingle roofs, cool roofing usually means choosing the right product when the roof is replaced.

Tile. Light-colored concrete and clay tile reflect a fair amount of sun, and tile has another advantage: it sits up off the deck with an air space beneath it that slows heat reaching the attic. Some manufacturers list specific tile colors in the CRRC directory.
Cool-rated shingles. Reflective granules raise reflectance without a white roof. Asphalt shingle replacement runs about $4.00 to $6.50 per square foot, with cool-rated shingles at the higher end.
Metal. Standing-seam and stone-coated steel come with factory finishes, many of them cool-rated. Standing seam runs about $9.50 to $14.00 per square foot, stone-coated steel about $8.00 to $12.00.

What we don't recommend: painting or coating an existing tile or asphalt shingle roof to make it cool. Tile and shingle roofs are designed to shed water, and coatings can trap moisture, change how water drains between tiles and affect warranties. Fontana's G40 underlayment warranty, for example, excludes damage from paints and coatings. If your pitched roof is due for replacement, that's the time to pick a cooler product.

Where a cool roof makes the biggest difference

How much a cool roof saves depends on the house. Researchers and utilities consistently find the biggest gains when:

The house is single-story, so the roof covers all the living space.
Attic insulation is thin, so more roof heat reaches the rooms.
AC ducts run through the attic, as they do in many Valley homes, so the ducts sit in cooler air.
The roof is flat or low-slope and faces the sun all day.
The current roof is dark, so the jump in reflectance is large.

The benefits shrink with a two-story house, deep attic insulation or a roof that's already light-colored. In Phoenix, the winter heating penalty that cool roofs carry in cold climates is small, because heating needs here are modest.

We don't put a dollar figure on savings, because it varies too much with insulation, ductwork, AC efficiency and your utility rate plan. A cool roof will make the roof itself last longer and run cooler; for the bill, treat it as one piece along with insulation, ventilation and a radiant barrier.

Rebates and incentives that actually exist

Incentives change often, so here's what we could verify as of fall 2026:

SRP. SRP offers residential customers a cool roof rebate of 30 cents per square foot, up to $600, on installed cool roofing that meets CRRC-rated reflectance thresholds (for example, an initial solar reflectance of at least 0.83, or a three-year aged reflectance of at least 0.70, or a three-year aged SRI of at least 86). The roof pitch must be 2:12 or less, and the home must be cooled by electric refrigerated air or evaporative cooling. Under its current terms, the work must be installed by April 30, 2027, and the rebate submitted within 6 months of installation. Check SRP's current terms before you start.
APS. If you're an APS customer, check APS's current rebate list before you start; we didn't find a residential cool roof rebate to point you to.
Federal tax credit. The federal 25C energy efficient home improvement credit ended for property placed in service after December 31, 2025, so don't plan on a federal credit for a roof installed now.

If you plan to apply, ask your roofer for the exact product name and its CRRC listing before the work starts, since you'll need them for the application.

Keeping a cool roof cool

A cool roof's reflectance drops as it gets dirty or as its coating wears. A little care keeps it performing:

Rinse or clean flat-roof coatings as the coating maker recommends. Phoenix dust and haboob grit dull a white roof fast.
Keep drains and scuppers clear so ponding water doesn't leave dirt rings and stains.
Inspect foam coatings for thin spots, cracking, blisters and bird pecks, and recoat before the foam is exposed.
Keep foot traffic to walk pads around rooftop AC units.
On tile and shingle roofs, replace broken tile and keep valleys clear; a cool surface does nothing if water is getting in.

Our maintenance plans include scheduled inspections: Essential is $199 a year for one visit, Premium $349 for two visits with minor repairs up to $200 included, and Ultimate $599 for four visits with minor repairs up to $300 included and priority scheduling.

Choosing a cool roof for your home

A simple way to decide:

Flat roof with sound foam: a reflective recoat is the cheapest way to a cool roof.
Flat roof with saturated foam or a failing membrane: new foam or white TPO.
Pitched roof due for replacement: light-colored tile, cool-rated shingles or cool-finish metal, checked in the CRRC directory and approved by your HOA.
Pitched roof in good shape: leave it, and look at attic insulation, ventilation and a radiant barrier instead.

Our standard roof inspection is free. We'll tell you whether your roof is a good candidate for a cool upgrade now or at its next replacement, and our estimates list the exact products so you can look up their ratings yourself.

Frequently Asked Questions

How much cooler is a cool roof in Phoenix?

According to the U.S. Department of Energy, a standard or dark roof can exceed 150 degrees in summer sun, while a cool roof under the same conditions can stay more than 50 degrees cooler. How much of that reaches your rooms depends on attic insulation, ventilation and whether AC ducts run through the attic.

Does SRP offer a cool roof rebate?

Yes. SRP currently offers residential customers 30 cents per square foot, up to $600, for qualifying cool roofing on roofs with a pitch of 2:12 or less. Products must meet CRRC-rated reflectance thresholds, the home must have electric refrigerated air or evaporative cooling, and the rebate must be submitted within 6 months of installation. Check SRP's current terms before starting.

Do cool roofs have to be white?

No. Cool-colored products use pigments that reflect invisible near-infrared sunlight while looking tan, gray, brown or terracotta. They don't reflect as much as white, but they reflect noticeably more than standard products of the same color. Cool-rated shingles, cool-finish metal and light tile colors all work this way, which helps where HOAs restrict roof colors.

Can I coat my tile or shingle roof to make it a cool roof?

We don't recommend it. Tile and shingle roofs are built to shed water, and coatings can trap moisture, change how water drains and affect warranties. Fontana's tile underlayment warranty, for example, excludes damage from paints and coatings. Coatings are the right tool for foam and other flat roofs. For a pitched roof, choose a cooler product at replacement.

Is there a federal tax credit for a cool roof?

Not for roofs installed now. The federal 25C energy efficient home improvement credit ended for property placed in service after December 31, 2025. The ENERGY STAR program for roofing products also ended in 2022. Utility rebates, such as SRP's cool roof rebate for low-slope roofs, are the main incentive to check today.

How do I compare cool roof products?

Look them up in the Cool Roof Rating Council directory, which lists tested solar reflectance and thermal emittance, both new and after three years of outdoor weathering. Use the three-year aged numbers, because dust and weather lower reflectance over time, and Phoenix is dusty. Ask your roofer for exact product names so you can check them yourself.